Ask HN: What's so different about Worlde, Flappy Bird etc.?

Wordle had a social aspect that allowed its users to share their progress/solutions in a visual format. It was perfectly adapted for social media.

I'd say the ability for anyone to understand and find it a challenge. No need to read the instructions, no need to get the keys - you just get it. Definitely the simplicity & broad engagement factor above all.

My impression is simplicity and shareability. It allows a large audience to get into the game easily and share and compete with/against their friends and others

I think what raised these above other simple shareable examples though is the low cost of engagement. No login, No signup, No Install. Just load page, and sharing was via the built in clipboard. Starting was essentially 0 cost. Sharing was 0 cost. Getting your friends or family to start was incredibly easy.